In Avengers, Hawkeye will perhaps be a useless character. Marvel studios will cram him into the plot just for the sake of it, and it will turn out pointless. I imagine Hawkeye to be just a background character, and that's less important than a ordinary supporting character.
All this gives room for DC Entertainment to come up with something that will give Green Arrow the edge over Marvel's copy. By the end of 2012, in the aftermath of Avengers, a script will be in the works. The film will come out by late 2014 or early 2015, and it will show the world that a superhero archer not only works in a blockbuster, but also also works as the MAIN character in a blockbuster. And then everyone will forget the failure of Hawkeye.